Septa Mordane tutors Arya and Sansa in needlework. She compliments Sansa on the skill of her work, but doesn't remark on Arya's grudging efforts.[1] Mordane accompanies Arya and Sansa to King's Landing and dines with them. She is present at the meal when Arya threatens to kill Joffrey Baratheon for his actions on the Kingsroad and reports this to her father. When Sansa is disdainful of the doll which Eddard Stark gives her and asks to be excused, it is to Septa Mordane that he says, "War was easier than daughters".[2] Mordane shows Sansa the throne room as part of Sansa's tutoring on the history of the Seven Kingdoms. Sansa is concerned over what will happen if she has no sons, only daughters, a concern that Mordane dismisses as highly unlikely.[3]

Mordane faces the Lannister soldiers

Mordane accompanies Arya and Sansa to the Hand's tournament and is present when Littlefinger explains the background of his nickname to Arya.[4] Mordane chaperones Sansa when Joffrey meets her to apologize for his behavior on the Kingsroad.[5]

She appears to not be as approving of Joffrey as she once was, but Sansa doesn't notice. Sansa is being rude to Septa Mordane (likely due to Cersei's example being a bad influence).

After the failed attempt by Sansa's father to remove Joffrey from the Iron Throne following King Robert's death, Mordane hears combat in the courtyard at the Red Keep. Fearing the worst she orders Sansa to run to her room and bar the door to anyone she does not know. After Sansa leaves, Mordane is confronted by several Lannister soldiers.[6]

Mordane's head

After the North rises in rebellion, Joffrey takes Sansa to the Traitors' Walk and forces her to gaze at her father's head on a spike. He also reveals that he needlessly had Mordane beheaded, and her head placed on a spike next to her father's.[7]

In the A Song of Ice and Fire novels, Septa Mordane is a loyal servant of House Stark, despite the fact that most of the family worships the Old Gods of the Forest rather than the Seven. She finds Sansa to be a willing, able and promising student. She despairs at the tomboyish Arya, who'd rather be running around the castle and playing with swords. Arya hates to do needle work and when she runs off to watch sword practice, she returns to her room to find Septa Mordane and her mother waiting to have words. Despite this rebellion, she is fond and fiercely protective of both of her charges.

She travels to King's Landing with Eddard Stark and his daughters. Arya is angry when she hears her praising Princess Myrcella's needlework even though it's not much better than Arya's own, which is always found wanting.

Septa Mordane goes to the Hand's tourney with Sansa and Jeyne Poole and must leave when Jeyne gets distraught witnessing the death of Ser Hugh of the Vale, pierced in the neck by a splinter of a jousting lance directly in front of them. She leads Jeyne away. Later the Septa chaperones Sansa to the post tourney feast and they are both encouraged to drink wine by Joffrey. When Sansa is ready to go she realizes that Septa Mordane is laying face down on the table asleep and accepts Joffrey's offer of an escort, but Joffrey then tells the Hound to do it and leaves them.

Sansa is not with Septa Mordane when the attack on Eddard Stark's people takes place in the book. Sansa went to Queen Cersei to plead for her to talk to Lord Eddard after he told Sansa that she and Arya were going to be taken out of the Keep by Stark men and taken to the docks to board a ship for Winterfell. Sansa is so distraught over leaving King's Landing and the breaking of her betrothal to Joffrey, she doesn't know she is betraying her father and putting them all in peril. Cersei promises to help, but then has Sansa escorted to a tower room and locked in under guard. Later Jeyne Poole is pushed into the room and they are both kept there for three days with no idea of what is occurring, other than the little that Jeyne saw of Stark men being killed.

Sansa is shown Septa Mordane's unrecognizable head on a spike by Joffrey, when he takes her to see her father's head up on the walls, and she asks why she was killed as she was god sworn, but Joffrey doesn't answer.